A 120v heater takes time to heat water on a cold fill so don't depend on that. The wattage draw is limited so the machine's control electronics and motor can also run.

Thanks. So keep running the sink to full hot before starting the machine?

I do not know, but my best guess (after lots of reading about this over the years) is that Allergy and Sanitize cycles are the only times an internal heater kicks in, unless the washer is a European brand.

So yes, keep priming the sink pipes before starting the machine.

I have a six year old Whirlpool front load (same manufacturer) and the heater does activate on the whites cycle if set to hot. Works great!

Heater functioning depends on the cycle programming firmware, which is not documented in detail by either the user manual or service manual. The only way to know for sure when the heater is operating (other than if the water has obviously been heated to a noticeably higher temperature) is by monitoring the amperage or wattage draw. That can be done via a Kill-A-Watt meter but it must be accessible/viewable while the machine runs. The meter plugs into the wall outlet like a surge supressor, the washer plugs into the Kill-A-Watt.

Thanks, Steven. I will listen closely but I am pretty sure mine doesn’t activate. The one shortcoming of this Maytag is the lack of solid info (in the owner’s manual or online) about what goes on with each cycle. Speed Queen manuals break it down almost minute by minute. Also, my glass door NEVER gets hot. But the design is very thick. I envy your third rinse!

Next to post a question about water hammer … .

Different brands from the same parent manufacturer and even different models of the same brand won't necessarily exhibit the same operating characteristics. Washers have become individual in their control programming. A given model at the beginning of a production year may also have programming changes later in production. The only way to expect two machines to be identical is if the model numbers, including any engineering change designation, are exactly the same ... and that neither one has had a control board change because a replacement part may be an updated version.

What model Mayatag front loader is this? Have you tried using the extra hot water temp on Whites cycle? Also, normal soil level may not always trigger the onboard heater as opposed to the heavier soil level.